One of the helpful things that Slack can do is keep track of the messages you have and have not seen. Part of this process relies on tracking when you last looked at each of the channels you’re a member of. Then monitoring which messages have been sent since then. If a channel has one or more messages posted since you last looked at it, then the channel is marked as having unread messages.
By default, the next time you go into a channel with unread messages, Slack starts you at the last read message. Then immediately marks all messages in the channel as read. Starting you at the last message you read is intended to make it easy to read through and catch up on all of the messages you missed. Immediately marking the entire channel as read when you open it can make it easier to quickly go through all of your channels and mark them as unread. Realistically, it would be easier to use the “Mark all as read” keyboard shortcut if you want to do that.
How to Stop Mark All as Read on Slack
Mark all as read allows you to quickly mark all channels as being read. This can be particularly useful if you’ve been away for a while, on holiday, and don’t want to read through a weeks’ worth of messages that probably aren’t important anymore in multiple channels. To mark all channels as read, you need to press the keyboard shortcut Shift + Esc. When you do so, a popup will appear to confirm that you want to mark everything as read. To proceed, click “Yes, clear all.”
If you want to prevent the popup from appearing, you can tick the checkbox in the popup labeled “Please don’t ask me again” before clicking “Yes, clear all.” Alternatively, you can go into your preferences and untick the “Prompt to confirm” checkbox in the “Mark as read” tab.
Using mark all as read is a quick and helpful way to deal with many unimportant unread messages. If you follow this guide, you can avoid having the confirmation popup appear every time you try to mark all as read.